1. Field of the Invention
The present invention is related to a molding method for molding a product which has a female screw section.
2. Description of Related Art
Conventionally, a component is die-cast of an aluminum alloy, and subsequently machining work (i.e., tapping) is performed to the component, so that a connecting component having a female screw is manufactured.
According to JP-A-2-187243, a core pin is provided in a casting die. A molten metallic material is filled into the molding die, and the filled metal is cooled. Subsequently, the core pin is drawn while being rotated, after the filled metal is solidified, so that a component with a female screw can be integrally formed when the component is formed by die-casting.
However, in this case, if an aluminum-alloy material is used as a casting material, the aluminum alloy is apt to stick to the core pin. Accordingly, the threads may be broken when the core pin is rotated and drawn. Therefore, it is hard to stably form the female screw in the component. On the contrary, if the female screw is tapped in the die-cast component made of aluminum-alloy material, manufacturing process becomes complicated.